From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Glider towing forces, quoting an extract from 'the Sailplane' magazine.
| Identifier | ExFiles\Box 175\2\ img007 | |
| Date | 21th October 1940 | |
| To Rs.{Sir Henry Royce's Secretary} from Rs{Sir Henry Royce's Secretary}/WH. Copy to Dr. Rs{Sir Henry Royce's Secretary}/WH.S/57.21.10.40. GLIDER TOWING FORCES. -------------------- For your information, we give below an extract from the "Sailplane" of July/Aug. 1940:- "The results of some experiments on gliders in towed flight made by the Soaring Society of America in 1937 have recently been published." "The cable tension and direction were photographically recorded together with a record of the velocity and acceleration of the glider in auto-towed and aero-towed flights, which included deliberate "porpoising" and yawing. The cable tension did not exceed 1.6 x gross weight of the glider, and the recorded accelerations ranged from 3g to -1g." "The cable tension did not exceed 200 lbs. during normal auto-launches to 700 ft., and on one occasion an auto-launch to 300 ft. was made with the pilot holding the upper end of the tow cable in his hand! The aero-towing force at about 60 m.p.h. averaged 65 lbs., with a maximum peak of 130 lbs." "These tests show that under normal conditions the towing cable tensions are not greater than the gross weight of the machine, and that a weak link failing at twice the gross weight would be satisfactory. A.H.Y." "N.A.C.A. Technical Note No. 753; "Measurement of the forces acting on gliders in towed flight," by W.B. Klemperer, Feb. 1940." We are trying to obtain a copy of N.A.C.A. Technical Note No. 753. Rs{Sir Henry Royce's Secretary}/WH. | ||